The bedtime book you don't dare read to your kids — "There’s a reason that the No. 1 title on Amazon last week was a still-unpublished rhyming picture book called Go the Fuck to Sleep—a Facebook gag turned PDF samizdat turned publishing sensation. Or there are two reasons, interrelated. The straightforward, surface one is that it’s accurate: “I know you’re not thirsty. That’s bullshit. Stop lying. / Lie the fuck down, my darling, and sleep.”

Last fall, Kanye West, a zealous user of Twitter, coined the phrase “hashtag rap” to describe analogies in rap lyrics that use a comic pause where the words “like” or “as” might be expected. West explained that this style conveys the rhythm of the pound-sign in online hashtags. Consider lines from the rapper Drake like, “Two thumbs up [PAUSE] Ebert and Roeper” and “I could teach you how to speak my language [PAUSE] Rosetta Stone.” Hashtags have become a big part of the rhythm of online communication — on the social networks, but even in e-mail and texts. Leave it to West and Drake to formalize them as prosody.